Complication of nitroprusside therapy.

Gated cardiac blood pool scans were obtained using a single crystal Anger camera with a general purpose collimator. In vivo labelling of the red blood cells with 20 mCi of technetium activity was done and a best septal view was obtained. The acquired data were processed using an Elscint AQ-75, DPT-3 acquisition unit equipped with the Dycom-80 program. Each cardiac cycle was divided into 24 frames consisting of a 64 x 64 byte mode matrix. A total of 6.0 million counts were acquired during each study. After processing, each study was viewed on a standard 12 inch video monitor and simultaneously viewed on a Tektronix 606 monitor ( a high reso1ulion flat oscil’oscope). Each frame was displayed full screen and then rotated 90#{176} counterclockwise. The rotated image was then photographed off the oscilloscope using standard film used in the cardiac catheterization laboratory ( Eastman Kodak CFR). The camera used for photography was a 35 mm still camera with a high resolution macro lens. The exposed film was then developed with other films in a bulk processor. The developed film was spliced end to end to make a film ioop containing the 24 frames generated from the cardiac cycle. Four blank frames were added to each loop for ease in identifying the beginning of the cardiac cycle. The loops were then viewed on a Tagarno cardiac catheterization projector ( Fig 1).